Traumatic brain injuries can result in physical and emotional dysfunction. Given the prevalence of age-related cognitive decline conditions, injury from a fall, cerebral-vascular events, neurodegenerative conditions (i.e., Alzheimer's Disease) and the many brain injuries occurring in sports and in military operation theaters, there is a need to develop a therapy for these diseases. Therapeutic stimulation modalities have had a key role in development of treatment for a number of neuropsychiatric disorders. Stimulation of tissue in humans and other animals is used in a number of clinical applications as well as in clinical and general biological research. In particular, stimulation of neural tissue has been used in the treatment of various diseases, including Parkinson's disease, depression, and intractable pain. The stimulation may be applied invasively, e.g., by performing surgery to remove a portion of the skull and implanting electrodes in a specific location within brain tissue, or non-invasively, e.g., transcranial direct current stimulation and transcranial magnetic stimulation.
There are two types of noninvasive brain stimulation techniques in the research literature, transcranial magnetic stimulation and transcranial direct current stimulation. There are subcategories within these two types of stimulation. TMS can be delivered as a continuous wave of stimulation, pulsed (repetitive or rTMS), or as a burst (theta-burst TMS). The other method uses electrical rather than magnetic stimulation and can be delivered through transcranial direct current (tDCS) or pulsed current (tPCS).
Direct current stimulation has been shown to be well tolerated in applications to the brain through the skull or cranium. It is described as transcranial direct current stimulation and is accomplished by multiple devices that generate continuous low current ion flow through the skull into the brain tissue. Other forms of brain stimulation involve creating holes in the skull and implanting a variety of energy transmitters.
Transcranial current stimulation (TCS) is a neuromodulation method in which the patient is exposed to a mild electric current (direct or alternating) at 1-2 mA, resulting in an increase or decrease in brain excitability. Considerable methodological details on using TCS in basic and clinical neuroscience studies in human subjects have been introduced and technical characteristics of TCS devices and their related accessories with regard to safety concerns have also been well articulated (C. Rossi et al., European Journal of Neurology 2013, 20: 202-204; Maryam Rostami et al., Basic and Clinical Neuroscience, 2013, Vol. 4, No. 3, pp. 8-26).
US20090319002 A1 relates to systems, apparatus and methods for applying electric current to neurons in the brain to treat disorders and to improve motor and/or memory functions in a patient, wherein an electrode is positioned adjacent to and spaced from the skin surface of the patient's head and an electric current is applied through the electrode to a target region in the brain to modulate one or more neurons in the target region. US20130281759 A1 provides a joint brain electro-analysis and transcranial current stimulation system comprising a plurality of spaced-apart removable and replaceable electrodes arranged in a piece of headgear, an electroencephalography device wired to each of the electrodes, and a transcranial current stimulation device wired to each of the electrodes. US20140018881 A1 provides a device for transcranial stimulation comprising an alternating current source for providing a stimulation current; a first electrode connected to the current source for electrical connection to a patient; a second electrode connected to the current source for electrical connection to the patient; a first current interrupter for interrupting current flow between the current source and the electrode, the first current interrupter connected between the alternating current source and the first electrode; and an output monitor connected between the current source and the first electrode for monitoring current to the patient.
Lindsay Oberman et al. highlight the need for rigorous documentation of adverse events associated with theta-burst stimulation (TBS), as well intensity dosing studies to assess the seizure risk associated with various stimulation parameters (e.g. frequency, intensity, location) (J Clin Neurophysiol. 2011 February; 28(1): 67-74). Continuous theta-burst stimulation (cTBS) applied over the cerebellum exerts long-lasting effects by modulating long-term synaptic plasticity, which is thought to be the basis of learning and behavioral adaptation.
However, there is a need to develop a transcranial electrostimulation system providing better brain or neuronal plasticity and treatment efficacy.